<i>W</i>-Band Compact Triple-Mode Bandpass Filter Using Multistub Resonator in 65-nm CMOS Technology

This letter presents a novel W-band compact wideband triple-mode bandpass filter (BPF) using multistub resonator. The resonator is loaded both by T-shaped stepped impedance stub (TSIS) and symmetrical open stub pair (SOSP) to generate three resonant modes and two transmission zeros for improving the bandwidth and enhancing the stopband rejection ability. Moreover, the characteristic admittance ratio has the ability to flexibly adjust the bandwidth and the transmission zero. The proposed BPF is fabricated in 65-nm CMOS technology with a core area of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$444\times 192~\mu $ </tex-math></inline-formula>m2. The measurement results show that the 3-dB bandwidth is 30.7 GHz at the center frequency of 94 GHz, the minimum insertion loss is 4.3 dB, and the stopband rejection is better than 20 dB.